Furnace-regulator system



Mar. 27, 1923. 1,449,884. C. A. BODDIE.

FURNACE REGULATOR SYSTEM.

FILED Aue.26.1s|9.

WITNESSES: I INVENTOR )05 4 C/arence ABOdd/g,

Patented Mar. 27, 1923.

UNITED STATES PATENT OFFICE.

CLARENCE A. BODDIE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

FURNACE-REGULATOR SYSTEM.

Application filed August 26, 1919.. Serial No. 319,906.

To all whom it may concern:

Be it known that I, CLARENCE A. Booms, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Furnace- Regulator Systems, of which the following is a specification. 7

My invention relates to regulator systems and particularly to regulator systems for governing the operation of the movable electrodes in electric furnaces.

()ne object of my invention is to provide a furnace-regulator system that shallop erate the movable electrodes in an efficient eration of the motor in accordance with the 2 current flowing through the electrode associated with it. Such means for regulating the operation of a furnace is fairly satisfactory under normal operating conditions but it is difficult to obtain satisfactory or close regulation unless some means is provided to'prevent the so-called hunting action.

In a furnace-regulator system constructed in accordance with my invention, each movable electrode is operated in accordance with the current flowing through it and means is provided for preventing overtravel of the various -parts of the regulator associated with each electrode and, accordingly,

for preventing so-called hunting action.

In practicing my invention, each movable electrode is provided with an electrode motor for raising and lowering it and a main control element which is governed in accordance with the current flowing through the associated electrode, is provided for governing the operation of the electrode motor. The main control element associated with each electrode comprises a main magnet which is energized in accordance with the current flowing through the electrode and an auxiliary magnet which is operated by the main magnet to prevent hunting action. The main magnet selectively operates two switches for rotating the electrode motor in a clockwise or in a counterclockwise direction to maintam a constant current flow through the electrode. The auxiliary magnet is mechancally connected to the main magnet, here- 111 shown to be by a fluid connection, but any other energy transmission connection may. be used and is provided with a resistor in its energizing circuit which is varied by the switches to vary the operation of the auxiliary magnet to react on the main magnet, and prevent hunting action. Thus, upon operation of the main magnet, one of the switches changes the energization of the auxiliary magnet which, in turn, changes the set-ting of the main magnet in a manner to prevent overtravel and the so-called hunting action.

The single figure of the accompanying drawing is a diagrammatic view of a regulator system embodying my invention.

Referring to the drawing, an electric furnace l, embodying a receptacle 2 containing a bath of material 3 and three movable electrodes 4, 5 and 6, is directly connected to a three-phase supply circuit comprising conductors 7, 8 and 9.

Each of the movable electrodes is controlled by a regulator in accordance with the current fiowin through the electrode and, inasmuch as t ese regulators are similar in construction and operation, only one regulator, namely, the regulator associated with the electrode 4, will be described in detail.

A motor 10, comprising an armature l1 and a field winding 12, is provided for raising and lowering the electrode 4. The field winding 12 is directly connected across a supply circuit comprising conductors 33 and 34. In the system shown in the drawing, the'motor 10 is connected to the electrode 4 by means of a windin drum l3 and a flexible connector 14 whic passes over a pulley 15 but it is to be understood that any other suitable connection may be provided for operating the electrode 4 by means of the motor.

A regulator, comprising a main control element 16'and two switches 17 and 18, is provided for governing the operation of the motor 10 to maintain constant current flow through the electrode 4. The main control element 16 embodies a main magnet 19 and is directly connected to a contact arm 24 andis provided with a piston 25 which operates within a cylinder 26 for a purpose to be hereinafter set forth. The contact arm 24 is fulcrumed at 27 and carries av main contact member 28 whicl: engages contact members 29 and 30, according to the operative position of the main electro-magnet 19.

The auxiliary electromagnet 20 comprises a winding 31 which is connected, in series with the variable resistor 32, across the auxiliary supply circuit comprising conductors 33 and 34. The winding 31 operates the core armature 35, which is supported by a spring member 36 and is provided with a piston 37 which operates within a cylinder 38. The cylinder 26', which is associated with the electromagnet l9, and the cylinder 38, which is associated with the electromagnet 20, are connected by a pipe 40 containing any suitable fluid, preferably oil, in order that any movement or action of the auxiliary electromagnet 20 may be transmitted to cause a corresponding effect upon the mainmagnet 19.

The switch 17 comprises a winding 41, which is connected across the supply conductors 33 and 34 upon engagement between the main contact members 28 and 29, and a core armature 42. The core armature 42 operates two switch members 43 and 44 and two interlock switch members 45 and 46. The two switch members 43 and 44 serve to connect the armature ll of the motor 10 across the supply conductors 33 and 34 to effect rotation of the motor in a clockwise direction to raise the electrode 4 from the bath of material 3. The interlock switch member 45 serves to short-circuit a portion of the resistor 32 which is included between taps 47 and 48 when the switch 17 is operated in order to increase the energization of thel auxiliary magnet 20 and to prevent socall (1 hunting action.

'llhe switch 18 comprises a winding 49, which is connected across the supply conductors33 and 34 upon engagement between the main contact members 28 and 30, and a core armature 50. The core armature 5O opcrates two switch members 51' and 52 and two interlock switch members 53 and 54. The two switch members 51 and 52 serve to connect the. armature 11 of the motor 10 across the supply conductors 33 and 34 in order to effect counterclockwise rotation of the motor to lower the electrode 4 in the furnace 1. The interlock switch 53', upon operation of the switch 18, serves to open a shortcircuit which normally exists across that portion of the resistor 32 which is included between the taps 48 and 55. The opening of such short-circuit across a portion of the resistor 32 decreases the energization of the auxiliary electromagnet 20 to prevent hunting action when the elect-rode 4 is being lowered into the furnace. The interlock switch members 46 and 54 serve to connect a braking relay 56 across the supply conductors 33 and 34 upon the simultaneous release of the switches 17 and 18. The relay 56, upon operation by the interlock switch members 46 and 54, completes a dynamic-braking circuit through a resistor 57 in order to efi'ect a quick stopping of the motor ll).

In case a current above normal value flows through the electrode 4, the energization of the main magnet 19 is increased to operate the contact arm 24 and to effect engagement between the contact members 28 and 29. Upon engagement between the contact members 28 and 29, a circuit is completed through eration of the switch members 43 and 44.

The switch members 43 and 44 connect the armature 11 across the supply conductors 33 and 34 and rotate-the motor 10 in a clockwise direction to raise the electrode 4 from the bath of material 3.

If the motor 10 were controlled solely by the effect upon the main magnet 19 of the current flowing through the electrode 4, the contact arm 24 would not be moved to separate the contact members 28 and 29 until normal conditions obtained in the circuit connected to the electrode 4. Consequently, by reason of the inertia of the various moving parts of the regulator, it is apparent that the motor 10 would overtravel to raise the electrode 4 beyond the desired point and, accordingly, decrease the current flow through it below normal value. In order to prevent such operation, the operation of the auxiliary magnet 20 is varied to effect separation; of the same contact members just prior to the obtaining of normal conditions in the 11 and the contact members 28 and 29 are separated just prior to the obtaining of normal current flow through the electrode 4.

switch 18 for operating the switch members 51 and 52. The switch members 51 and 52 connect the armature 11 of the motor 10 across the supply conductors 33 and 34 to efl'ect rotation of the motor in a counterclockwise direction and, accordingly, to lower the electrode 4 in the furnace 1.

Upon operation of the switch 18, the interlock switch member 53 opens the short-circuit which normally exists across a portion of the resistor 32 in order to decrease the energization of the auxiliary magnet 20.

Upon decreasing the strength of the electromagnet 20, the pressure exerted on the piston 25 of the magnet 19, through the fluid connection, is decreased and, accordingly, the setting of the magnet 19 1s changed so that a separation ofthe main contact members 28 and 30 is effected just prior to the obtaining of normal conditions in the electrode circuit.

Thus, the main magnet 19 operates the switches 17 and 18 to control the motor 10 and raise and lower the electrode 4 to maintain a constant current flow through such electrode. The switches 17 and "18 also operate the resistor 32 to vary the energization of the auxiliary magnet 20 to change the setting of the main magnet 19 and prevent hunting action by the regulator.

In the claims, where the terms energy transmission connection or mechanical connection are used, it is to be understood that any non-electrical connection is comprehended that will permit the electromagnets to function as herein described.

In my copending application, Serial No. 342,17 5, filed December 3, 1919, I have illustrated, described and claimed a furnace-regulator system having other means for preventing hunting action.

Modifications in the system and arrangement and location of parts may be made within the spiritand scope of my invention and such modifications are intended to be covered by the appended claims.

I claim as my invention: 7

1. In afurnace-regulator system, the combination with a movable electrode and a motor for operating the electrode, of a main control element having a main electro-magnet and an auxiliary electromagnet for operating said motor to maintain constant current flow through said electrode, and a fluid connection between the main magnet and the auxilia magnet for controlling one magnet by the other magnet to prevent hunting action.

2. In a furnace-regulator system, the combination comprising a movable electrode,

means comprising a main control element for governing the operation of said electrode, said element comprismg a main mag- "net-operated in accordance with the current flowing throughthe electrode and an auxiliary magnet having a fluid connection with the main magnet, and means for varying the energization of the auxiliary magnet to operate the main magnet and prevent huntmg action.

3. In a furnace-regulator system, the combination with a movable electrode, and a motor for raising and lowering said electrode, of a main magnet operated in accordance with the current flowing through the furnace, means comprising contact members controlled by said main magnet for governing the motor to maintain a constant current flow through the electrode and an auxiliary magnet having a mechanical connection to the main magnet for operating it to prevent hunting action. a

4. In a furnace-regulator system, the combination with a movable electrode, of a main magnet operated in accordance with the current flowing through the electrode, two switches selectively operated by said mam magnet for controlling said motor, an auxiliary magnet having a mechanical connection to said main magnet, and means controlled by said switches for varying the energization of the auxiliary magnet to operate the main magnet and prevent huntlng actlon.

5. In a furnace-regulator system, a movable electrode, means for raising and lowermg said electrode, a main magnet for controlling the operation of said means to maintam a constant current flow through the electrode, an auxiliary magnet controlled by the main magnet and adapted to react on the main magnet to prevent hunting action.

6. In a furnace-regulator system, a movable electrode, means comprising a main electromagnet for operating "the electrode to maintain a constant current flow through it, and an auxiliary magnetcontrolled by the main magnet and reacting on the main magnet to prevent any hunting action.

Ina furnace-regulator system, the combmation comprising a movable electrode, means comprising a main magnet for operating the electrode to maintain a constant current flow throu h it, an auxiliary magnet having a variabIe resistor in circuit with it, means for varying said resistor in accordance with the operation of the main magnet and a mechanical connection between said magnets-for governing the main magnet in accordance with the operation of the auxiliary magnet to prevent hunting action.

8. In a regulator system, the combination comprising a supply circuit, a resistancevarying member in said circuit, means comprising a main magnet for operating said member to maintain a constant current flow through said circuit, an auxiliary magnet connected in circuit with a variable resistance, means for varying said resistor in accordance with the operation of the main magnet, and a mechanical connection between said magnets for governing the main magnet in accordance with the operation of the auxiliary magnet to prevent hunting action.

trode, an auxiliary magnet controlled by the main magnet, and a mechanical connection between said magnets for governing the main magnet in accordance with the operation of the auxiliary magnet to prevent hunting action.

10. In a furnace-regulator system, a movable electrode, means com-prising a. main electromagnet for operating said electrode in accordance with the electrode circuit conditions, and an auxiliary magnet for reacting on the main magnet to change its setting.

11. In a regulator system, the combina 'tionwith a supply circuit, a motor, and a control magnet operated in accordance with the current flowing through the supply circuit, of means controlled by said magnet for operating the motor in a forward and in a reverse direction and for establishing a braking circuit through the motor, and means for preventing hunting action in said system.

12. In a regulator system, the combination with a supply circuit, a resistancevarying member associated therewith, and means for operating said member, of regulator mechanism therefor comprising an electromagnet operated in accordance with the current in said circuit, a second electromagnet and energy-transmitting mechanism co-operating with said second electromagnet and being adapted to react on said regulator mechanism to prevent hunting action in said system.

13. In a regulator system, the combination with a supply circuit, a resistance-varying member associated therewith, and means for operating said member, of regulator mechanism therefor controlled in accordance with the current in said circuit comprising a plurality of electromagnets and energytransmitting mechanism connecting said electromagnets, one of which is adapted to act upon said regulator mechanism to prevent hunting action insaid system.

14. In a regulator system, the combination with a supply circuit, a resistance-varying member associated therewith, and means for operating said member, of regulator mechanism therefor controlled in accordance with the electrical characteristics of said circuit and comprising a main electromagnet and a reactive electromagnet adapted to control said regulator mechanism so as to prevent hunting action in said system.

15. In a regulator system, the combination with a supply circuit, a resistance-varying member associated therewith. and means for operating said member, of regulator mechanism therefor comprising a main electromagnet and a reactive electromagnet adapted to govern the operation of said regulator mechanism so as to prevent hunting action in said system.

16. In a regulator system, the combination with a supply circuit, a resistance-varyinglmember associated therewith, and means for operating said member, of regulator mechanism therefor comprising a plurality of electromagnets, and a vmechanical connection therebetween whereby one of said electromagnets may act on said regulator mechanism to prevent hunting action.

17 A regulator system comprising means to be regulated, and regulator mechanism therefor comprising a plurality of connected electroinagnets, one of said electromagnets being adapted to react upon said regulator mechanism to prevent hunting action in said system.

18. A regulator system comprising means to be regulated, regulator mec anism therefor comprising a plurality of electromagnets, and energy-transmitting means connecting said electromagnets, one of said electromagnets being adapted to. react upon said regulator mechanism through said connection to prevent hunting action in said system.

I In testimony whereof, I have hereunto subscribed my name this 12th day of Aug. 1919. 

